Application of the SWAT-EFDC Linkage Model for Assessing Water Quality Management in an Estuarine Reservoir Separated by Levees

Abstract

Estuarine reservoirs are available for use in various water resource systems. In agriculture, supplying irrigation water that meets water quality standards is essential for food safety. This study focused on the Ganwol estuarine reservoir in the midwestern region of South Korea, which suffers from water quality deterioration problems. To explore the water quality improvement in an estuarine reservoir, it is essential to understand the characteristics of water quality changes in the reservoir following water pollution control management. Therefore, the purpose of this study is to evaluate the effects of water quality management on the estuarine reservoir, which is separated by levees, using the soil and water assessment tool (SWAT)-environmental fluid dynamics code (EFDC) linkage model. In this study, soil remediation by dredging the reservoir’s bottom soil and effluent control from public sewage treatment works were considered as the water management plans. The results of this study indicate that reducing the internal load of the reservoir increases internal resilience and reducing the external inflow load decreases the impact on the system. Hence, comprehensive measures are effective in improving water quality.

A coupled 2D-3D catchment-lake model with a parallel processing framework

“…In addition, this approach generally disregards diffuse water and nutrient inputs that may occur through hillslope and groundwater transport. This limitation can be overcome by coupling catchment with lake hydrodynamic models (Hwang et al, 2021;Shin et al, 2019).…”

“…As an example, the EFDC model is one of the most used and technically defensible hydrodynamic model for hydrodynamic simulation (Lai et al, 2016). It is open source and can simulate one, two and three-dimensional flows, sediment transport, thermal and biological processes in rivers, lakes, reservoirs and estuaries (Hwang et al, 2021). The EFDC model is capable of simulating the wetting and drying process in lakes and can deal with transient and intermittent events of water, nutrients and sediments coming from rivers or hillslopes (Hamrick, 1992).…”

“…Regarding limitations in preprocessing and data sharing, they can be improved with the automation of the coupling process of the hydrological and hydrodynamic models for applications in lake ecosystems modeling (Alarcon et al, 2014;Gregersen et al, 2007;Hwang et al, 2021;Shin et al, 2019;Zhang et al, 2017). For example, Huang et al (2016) coupled a 2D hydrological model (Xinanjiang) and the Environmental Fluid Dynamics Code (EFDC) in which the Xinanjiang model simulates inflow discharges for the boundary conditions of the hydrodynamic model of Lake Chao, China.…”

“…Zhang et al (2017) coupled the Soil and Water Assessment Tool (SWAT) and the Delft3D model to simulate the interactions between water flows in ungauged zones of the catchment and Lake Poyang in China. Hwang et al (2021) used SWAT-EFDC to evaluate the water quality improvement scenarios considering the agricultural system and nonpoint source pollution of the upper Ganwol estuarine reservoir catchment located in South Korea. The models used in these studies are good alternative options, their coupling schemes disregard diffuse inputs and they are not implemented considering high-performance computing.…”

E-DBCM: A dynamically coupled upland and in-stream water quality model for watershed water quality simulation

“…The external coupling is the simplest and most common type. It usually uses hydrographs and pollutant load from the UWSM as the input for the DWBM, providing a one-way but seamless transition (Narasimhan et al, 2010;Shin et al, 2019;Hwang et al, 2021;Wang et al, 2021;Xue et al, 2021). However, since it does not consider the impacts of the DWBM on the UWSM, the accuracy of the output is hindered.…”